The present invention relates to a variable displacement oil pump.
U.S. Patent Application Publication No. 2009/0022612 (corresponding to International Publication No. 2006/066405) discloses a previously-proposed oil pump. In this technique, a control chamber is separately formed by providing a sealing member between a cam ring and a housing. Pressure of this control chamber swings the cam ring so that a capacity of the oil pump is variably controlled.